The present invention relates to a method and an apparatus for feeding automatically metal profiles in bar form, particularly iron rods for reinforced concrete, in machines for working said profiles.
It is known that the rods used, for example, to produce reinforcement frames for reinforced concrete can be obtained from iron rods in bar form. For this purpose, the bars are fed, individually or in groups, to machines that work them automatically into a series of intended products. The machines provide, if required, a suitable series of processes, in particular cropping the rods to size.
The bars are currently fed to said machines manually by an operator, who counts and picks up the initial portion of a group of bars from a collection magazine, also known as stock magazine, which is arranged in line with the machine, and inserts said bars through an inlet of the working components of the machine. The operator then starts the working cycle of the machine, which automatically draws the bars into the head, measures them, bends them if required, and crops them according to a program provided for this purpose.
Feeding the bars is particularly difficult for the operator, who is forced to work in a very noisy and potentially dangerous environment. The difficulty is further increased by the fact that said bar feeding must be performed relatively frequently. The bars in fact have a limited length, which leads to an equally limited, working time, due to the operating speed of the machine, and therefore leads to the need to feed the machine frequently.
It should also be noted that during this feeding step it is also necessary to determine the correct number of bars to be fed to the machine according to the working requirements. For example, the number of bars to be fed to the cutting elements of the machine is determined, in relation to the working capacity of said components, by the diameter of said bars, by the characteristics of the material being worked and by production requirements.
Italian patent no. 1,206,893 describes a device for feeding the profiles to a machine tool which comprises an opening in the upper part and a horizontal roller that is arranged in a fixed position below said transport opening, is provided with a helical groove and is associated with a transfer disk that has radial notches. The bundles of profiles are fed to the transport roller by virtue of suitable collet-type pick-up means, which must move the end of the bundle so as to move around the entire structure so as to reach the upper part where the opening is located. The transport roller and the transfer disk are motorized synchronously, so, as to produce the translational motion of profiles that rest tangentially at the helical groove and the subsequent transfer of the individual profiles, by virtue of said radial notches, to the machine tool.
Said feeder, however, is scarcely functional and not very versatile. The horizontal roller in fact picks up the, bars from the bundle picked up by virtue of said collet means starting from the bottom of the bundle placed in the inlet, where the bars are most entangled and are surmounted by the mass of the bundle. This makes traction difficult for the transport elements, owing to the higher friction that occurs between the contact surfaces, since the surfaces of the bars are normally ribbed. Moreover, changing from one type of work to another, for example to change bar length or diameter, is very complicated, because in order to be able, to move the machine with respect to the various storage units of the stock magazine it is necessary to clear the device of the residual bars, and this operation is not straightforward.
The aim of the present invention is to solve the cited problem by providing a method that allows to feed automatically the metal profiles in bar form in machines for working said profiles and to clear said machine immediately, so as to allow it to move immediately at the end of each working cycle.
Within the scope of this aim, an object of the present invention is to provide a method that allows to determine the correct number of profiles to be fed to the machine as a function of work requirements.
Another object of the invention is to provide an apparatus that allows to provide said method by means of a structure that is simple in concept, safety reliable in operation, versatile in use, low in cost and possibly applicable to existing machines with minimal modifications.
This aim and these and other objects are achieved, according to the present invention, by the method for feeding automatically metal profiles in bar form in machines for working said profiles, which is characterized in that it comprises the steps of:
(a). gripping a group of metal profiles in bar form or their end from a magazine for collecting said profiles;
(b). transferring said group of metal profiles in bar form or their end to a raised position;
(c). arranging under said metal profiles in bar form a transfer device provided with means for separating said profiles;
(d). transferring transversely said metal profiles in bar form and at the same time counting a preset number of metal profiles to be fed to the machine at each work cycle;
(e). unloading the excess metal profiles into the same magazine from which they originate;
(f). starting automatically the normal work cycle of the machine to perform the intended work on the selected metal profiles;
(g). optionally moving with respect to each other the machine and said collection magazine in order to pick up metal profiles from a different storage unit;
(h). starting an optional new work cycle by resuming from step (a).